Methods for directly making a printing plate, without outputting an image signal from a computer on photographic paper or a lith film, using an output device such as an electrophotographic printer, a thermal-transfer printer, or an ink-jet printer (direct plate-making methods) have recently been proposed with the development of business equipment and the progress of office automation equipment.
Among the direct plate-making methods, those using the ink-jet printer are advantageously capable of high-speed processing or the like, and various proposals have been made for the apparatus and the material to be used for the plate-making methods (Patent Documents 1 and 2).
In the methods using the ink-jet printer, when a metal support for a PS plate or a synthetic resin support composed of a polyester or the like, which do not have a layer capable of satisfactorily retaining an ink on the surface, is used without modification as a lithographic printing plate material, an excellent image cannot be formed due to bleeding of the ink on the surface. Therefore, an image-receiving layer for absorbing the ink is formed on the surface of the support. Such a material having the image-receiving layer has been developed in view of improving a balance between ink-absorbing capability and printability.